There's a lot of generalization from a single sample here:

> The world of single-child parenting, at least in my experience, was a doting dance. A universe where our child became the sole moon, and around him, our world orbited. ...when everything is handed over without a slight struggle or effort, it becomes the expected norm....[with multiple kids] Gone were the days of extravagant games and toys. In their place, the charm of simple play, conversations, and basic fun thrived.

A single child need not be a helicoptered princess/prince. That's a cultural or personal choice on the part of the parents. They can just as well grow up to be a happy, well adjusted adult experienced in both love and challenges.